<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="">
    <!-- 1.required必填项，内容不能为空-->
    <input type="text" required>
    <!--2.maxlength字符串最大长度-->
    <input type="text"  maxlength="15">
    <!--3.minlength字符串最小长度-->
    <input type="text" minlength="10">
    <!--4.max/min数值的最大/最小值 -->
    <input type="number" min="5" max="60">
    <!--5.pattern正则表达式-->
    <input type="text" placeholder="电话" pattern="1[3456789]\d{9}">
    <input type="submit">
</form>
    
</body>
</html>